Lithium location

Discussion about any electrical topic except 240 volts. Solar, converters, inverters, lights, battery chargers, etc
bobakers
Posts: 6
Joined: Mon Sep 18, 2017 10:54 pm

Lithium location

Post by bobakers »

Hi all

Am in the process of designing the layout for the camper body to go on the back of my 6x6 perentie. The original plan was agms mounted left hand side just behind the cab under the tray.
Now looking at using 300 ah Winston cells and am concerned about charging in cold weather and the robustness of the cell top bms boards. The inverter, solar reg, HVC/LVC and dcdc charger will all be mounted in a dedicated cupboard inside.
Would I be better off moving the battery inside or is it sufficient to just make up a box, mounted to the chassis for the lithiums?

Thanks
Bob
User avatar
T1 Terry
Posts: 15965
Joined: Fri Nov 23, 2012 3:44 pm
Location: Mannum South Australia by the beautiful Murray River
Has thanked: 50 times
Been thanked: 30 times

Re: Lithium location

Post by T1 Terry »

Hi Bob and welcome to the forum. A number of things you mentioned are not quite the way I'd recommend. I would use 3 x 100Ah cells in parallel and 4 packs of these in series to build the 300Ah @ 12v battery rather than using 4 x 300Ah cells in series. Using single 300Ah cells will send you around the bend trying to keep them in balance where 3 x 100Ah cells will balance out each others strengths and weaknesses to produce a much more user friendly pack.
Next, I'd recommend against using the BMS balance boards across the tops of the cells. A properly set up 12v battery doesn't need balancing equipment and the balance boards simply turn the electrical energy into heat energy when the go into balance mode. Heat is the lithium cell killer so the last thing you would want to be doing is adding heat inside the cell, these balance boards use the cell terminals as heat-sinks so that is exactly what happens. The next problem is the heat eventually punches through the small transistor on the board and then it becomes a continuous drain till it kills the cell, exactly the opposite outcome to very reason you install them in the first place.
Next, do not mount the cells under anything, you will hate yourself for doing it the first time you have to check the terminal bolts or connections. Mount the cells where you can get easy access and clear line of sight while your hands are working on the cells, a spanner across the terminals is easy done when you can see what you are doing, almost impossible to avoid if you can't see what you are doing.
A spanner across a cell looks like this viewtopic.php?f=14&t=5598 can you imagine what that would look like across 12v @ 300Ah instead of 3.2v @ 100Ah :shock:

T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
Those who struggle to become a leader, rarely know a clear direction forward for anyone but themselves
bobakers
Posts: 6
Joined: Mon Sep 18, 2017 10:54 pm

Re: Lithium location

Post by bobakers »

Hi Terry
Thanks for that, re read my post and didn't mean that I would be using just 4 x 300 ah cells.
Re spanner on the terminal post seen that happen with the LA batteries in the lcm8 I use to work on and would hate to see in on a lithium set up.
Really not interested in balancing type boards but did want to have individual cell monitoring so will have to do a lot more reading.
Regardless where the battery is mounted, clear access for maintenance will be a priority. If mounted under the body it would be on a slide out draw but I'm not sure if it woul be ok to be in an enclosure?

Thanks
Bob
User avatar
T1 Terry
Posts: 15965
Joined: Fri Nov 23, 2012 3:44 pm
Location: Mannum South Australia by the beautiful Murray River
Has thanked: 50 times
Been thanked: 30 times

Re: Lithium location

Post by T1 Terry »

bobakers wrote: Sat Apr 28, 2018 5:01 pm Hi Terry
Thanks for that, re read my post and didn't mean that I would be using just 4 x 300 ah cells.
Re spanner on the terminal post seen that happen with the LA batteries in the lcm8 I use to work on and would hate to see in on a lithium set up.
Really not interested in balancing type boards but did want to have individual cell monitoring so will have to do a lot more reading.
Regardless where the battery is mounted, clear access for maintenance will be a priority. If mounted under the body it would be on a slide out draw but I'm not sure if it woul be ok to be in an enclosure?

Thanks
Bob
A slide out battery tray is fine, the 1lyp chemistry can handle charging down to minus 20*C and I doubt you'd fine too many free camps down around that temp.

I haven't read it yet, but Margaret posted a few bits on her business website T1 Lithium. com.au and all the other mixtures of that like .info and .sales and what ever else. Might be something in there that helps.

T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
Those who struggle to become a leader, rarely know a clear direction forward for anyone but themselves

Return to “Low Voltage Electrical”